The present invention relates to an inflator/sealer device useful for inflating and sealing an inflatable cushion.
Packagers are increasingly using air-inflated cushions formed from relatively thin films of thermoplastic to protect their packaged goods within boxes, sleeves, or cases during shipping and storage. For example, an inflatable packaging cushion system that can protect a wide variety of packaged goods is sold by Sealed Air Corporation under the VISTAFLEX trademark. The VISTAFLEX inflatable packaging cushion includes an inflation inlet designed for use with an inflation/sealing machine provided by Sealed Air Corporation under the BT-1 trademark. As depicted in FIG. 1, the inflation inlet 12 of the inflatable cushion 10 has top and bottom sheets 14, 16 sealed at the peripheral zone 18 to form an inlet passageway 20. The BT-1 inflator/sealer controls both the inflation of the cushion with compressed air and sealing of the inflated cushion with an impulse heat sealer.
To inflate and seal the VISTAFLEX cushion, a user inserts the inflation tube 22 of the prior art inflator/sealer (not shown) into the inflation inlet 12 of the cushion 10. (FIGS. 2-3.) The inflator/sealer inflates the cushion by opening a valve to allow compressed air to pass through the inflation tube 22 into the interior of the cushion chamber 24 until the cushion chamber has been inflated to the desired pressure. (FIG. 4.) At that point, a heat seal bar 26 compresses the top and bottom sheets of inlet 20 to prevent the inflated cushion from deflating. (FIG. 5.) The heat seal bar includes heating element 28. An electric current passes through the heating element 28 to heat the element, which then conducts heat to the compressed top and bottom sheets of the inlet until the sheets reach the heat seal initiation temperature. The electric current is then discontinued to heating element 28 to allow it to cool while the heat seal bar continues to compress the top and bottom films. Once the resulting heat seal has cook point where the heat seal is set, the heat seal bar 26 disengages. (FIGS. 6-7.) The resulting heat seal 30 is formed transversely across inlet passageway 20 to seal cushion chamber 24 in the inflated state.
The BT-1 inflation system allows a packager to inflate and seal inflatable packaging cushions in a consistent, reliable, and easy manner at the site where the goods are to be packaged. For example, the BT-1 machine may complete an inflation and sealing cycle for a packaging cushion in about 8 seconds. Nevertheless, packagers desire an even faster and more reliable system for inflating and sealing inflatable packaging cushions.
The present invention addresses the aforementioned problems. A first aspect of the invention is directed to a machine for inflating and sealing an inflatable cushion of the present invention. The machine includes a base that supports an inflation tube, a seal bar, and an anvil. The inflation tube has an inlet portion connected to a source of inflation fluid and an outlet portion that is larger than the inflation aperture of the given inflatable cushion. The inflation tube and anvil are adjustable between a tube/anvil engaged position and a tube/anvil disengaged position. In the tube/anvil engaged position, the inflation tube outlet portion opposes the anvil. The inflation tube and the anvil are capable of engaging the inflation portion of the inflatable cushion between the inflation tube and the anvil. In doing so, the inflation tube outlet portion surrounds the inflation aperture and places the inflatable body of the inflatable cushion in fluid communication with the source of inflation fluid. In the tube/anvil disengaged position, the inflation tube and anvil are spaced apart so that the inflation portion of the inflatable cushion may be inserted or withdrawn from between the inflation tube and the anvil.
The seal bar and the anvil of the first aspect of the invention are adjustable between a bar/anvil engaged position and a bar/anvil disengaged position. In the bar/anvil engaged position, the anvil opposes the seal bar so that the anvil and seal bar are capable of compressing the inlet heat seal zone of the inflatable cushion between the anvil and the seal bar. In the bar/anvil disengaged position, the anvil and seal bar are spaced apart so that the inlet heat seal zone of the inflatable cushion may be inserted or withdrawn from between the anvil and the seal bar. Left and right contacts are positioned on opposing sides of the seal bar at least during the bar/anvil engaged position. The contacts are connected to an electrical power source. The contacts are capable of touching the resistance wire of the inflatable cushion to complete an electrical circuit during the bar/anvil engaged position.
A second aspect of the invention is directed to a machine for sealing an inflatable cushion of the present invention. The machine includes a seal bar and an anvil, which are adjustable between an engaged position and a disengaged position. In the engaged position, the anvil opposes the seal bar so that the anvil and seal bar are capable of compressing the inlet heat seal zone of the given inflatable cushion. In the disengaged position, the anvil and seal bar are spaced apart, so that the inlet heat seal zone of the given inflatable cushion can be withdrawn from between the anvil and seal bar. Left and right contacts are positioned on opposing sides of the seal bar when the seal bar and anvil are in the engaged position. The contacts are connected to an electrical power source. The contacts are capable of touching the resistance wire of the given inflatable cushion to complete an electrical circuit when the seal bar and anvil are in the engaged position.
A third aspect of the invention is directed to a machine for inflating an inflatable cushion of the present invention. The machine includes an inflation tube and an anvil. The inflation tube is connected to a source of inflation fluid. The outlet portion of the inflation tube is larger than the inflation aperture of the given inflatable cushion. The anvil defines a slot. The inflation tube and anvil are adjustable between an engaged position and a disengaged position. In the engaged position, the inflation tube outlet portion opposes the slot of the anvil. The inflation tube and anvil are capable of engaging the inflation portion of the given inflatable cushion between the inflation tube and the anvil so that the inflation tube outlet portion surrounds the inflation aperture of the inflatable cushion. In the disengaged position, the inflation tube and anvil are spaced apart, so that the inflation portion of the inflatable cushion may be inserted or withdrawn from between the inflation tube and the anvil.
The inflatable cushion of the present invention provides several advantages. Since the resistance wire heating element is positioned internally in the inflation inlet of the cushion, the resistance wire transfers heat directly to the portion of the cushion films that actually form the heat seal (e.g., the heat seal layers). There is no need to heat the outer portion or layers of the cushion material to heat seal the inlet passageway of the cushion. Further, since there is no need to heat any portion of the inflator/sealer device itself in order to heat seal the packaging cushion, the inflator/sealer may operate essentially at room temperature. It is only the relatively small resistance wire within the inflatable cushion that is heated to a heat seal temperaturexe2x80x94and that high temperature occurs on the inside of the inflation inlet of the cushion.
Since there is no need to conduct heat through the full thickness of the cushion films, as is required by an external heated-bar sealer (e.g., conductance-type heat sealer), the inflation inlet may be sealed more quickly than by the use of a conductance heat sealer. For example, the heat seal cycle time may be less than about 1 second, preferably less than about 0.5 seconds total for the heating and cooling cycle.
Further, by avoiding the use of a high-temperature sealing jaw of a conductance heat sealer, the present invention increases reliability while reducing the complexity, manufacture cost, and operating cost of the sealing units. There is no need to xe2x80x9cwarm upxe2x80x9d the inflator/sealerxe2x80x94nor does the inflator/sealer have elements, such as a heated jaw, whose temperature may change according to the heating demand and drift over the period of operation. The inventive inflator/sealer may be operated sequentially to produce a series of inflated/heat sealed cushions. In doing so, the inflator/sealer creates a stable heat seal environment that produces more uniform heat seals from the first heat seal in a series to the last.
The inflatable cushions may be provided in a deflated or flat condition, so that a stack or roll of the inflatable cushions occupy a relatively small amount of space. This minimizes the costs of shipping and storing the inflatable cushions. Further, the inflator/sealer device may be located at the end-user""s plant so that the cushions may be conveniently inflated, for example, just before the cushion is used in a packaging application.
These and other objects, advantages, and features of the invention will be more readily understood and appreciated by reference to the detailed description of the invention and the drawings.